Inflatable antenna



OC- 11, 1966 M. M. RosENTHAL INFLATABLE ANTENNA 2 Sheets-Sheet l Filed Jan. 29. 1963 Oct. 11, 1966 M. M. Rosx-:NTHAL INFLATABLE ANTENNA 2 Sheets-Shea?I 2 Filed Jan. 29,. 1965 United States Patent O 3,278,938 INFLATABLE ANTENNA Myron M. Rosenthal, North Massapequa, N.Y., assignor to Loral Electronics Corporation, Bronx, N.Y., a corporation of New York Filed Jan. 29, 1963, Ser. No. 254,650 4 Claims. (Cl. 343-880) This invention relates generally to the field of radio reception and transmission, and more particularly to an improved collapsible antenna requiring a minimum of elfort to erect the same to operable condition.

Present-day troop and military cargo carrier aircraft have equipment that can be used to facilitate operations in areas which are relatively diiicult, sometimes impossible, to reach by surface motor vehicles. In certain of these operations, the surrounding terrain is such that deltection and location of paratroop teams on the ground is not possible Without a beacon or other homing device. For example, a jungle in which the average `tree height may approach 100 feet can easily hide the presence of the team from the aircraft seeking to effect a rendezvous. Further, contact and rendezvous must be made as quickly as possible to avoid enemy air assaults and possible enemy attacks.

It is known in the art to provide an inflatable antenna which can be hand-carried into a dense area or dropped along with a paratroop team. This structure has alleviated one phase of the problem, but has left unsolved the problem of erecting the antenna for use on the ground. In prior art structures, the antenna is usually completely inliated at ground level, and then raised into a vertical position with the help of several men and some type of hoisting mechanism. It is obvious that when operating in dense areas or undeveloped terrain, the erection of an antenna 100 feet long, although Weighing only several pounds, by such method may be impossible. It initially requires the hacking away of underbrush at ground level for a distance equal to the length of the antenna. On completion of inliation, the overhanging area would then have to be cleared so that erection could take place without damaging the walls of the antenna. These requirements have greatly reduced the effectiveness of such antennas in such areas where their need is of prime importance.

It is therefore among the principal objects of the present invention to provide an improved pneumatically inflatable antenna of the class described in which the above-mentioned disadvantages have been substantially eliminated.

Another object of the invention lies in the provision of an improved inatable antenna which may be conveniently handled by one man during Ithe erection procedure thereof, and in which erection takes place progressively in a vertical orientation, starting with the uppermost portions.

A further object of the invention lies in the provision of improved means for controlling progressive erection of an iniiatable antenna, wherein the already inated portions become immediately self-supporting, and provide a vertical force which draws the remaining folded and unintiated sections into vertically elongated condition for subsequent ination.

A feature of the invention lies in the relatively small volume occupied by a collapsed antenna in folded condition.

3,278,938 Patented Oct. 11, 1966 Another feature of the invention lies in the fact that the entire device may be constructed of relatively low cost materials, whereby the same may be completely expandable after a single use.

These objects and features, as well as other incidental ends and advantages, will more fully appear in the progress of the following disclosure, and be pointed out in the appended claims.

In the drawings, to which reference will be made in the specification, similar reference characters have been ernployed to designate corresponding parts throughout the several views.

FIGURE 1 is a fragmentary partially schematic vertical sectional view of a first embodiment of the invention.

FIGURES 2, 3 and 4 are perspective views showing progressive inflation and erection of the first embodiment.

FIGURE 5 is a fragmentary view in elevation, partially in section, showing a second embodiment of lthe invention.

FIGURE 6 is a fragmentary sectional view showing the composition of iiexible material employed in the formation of both the first and second embodiments.

FIGURE 7 is a fragmentary enlarged vertical sectional view as seen from the plane 7 7 in FIGURE 8.

FIGURE 8 is a transverse sectional view as seen from the plane 8 8 in FIGURE l.

FIGURE 9 is a fragmentary partially schematic vertical sectional view of a third embodiment of the invention.

FIGURE 10 is a fragmentary partially schematic vertical sectional view of a fourth embodiment of the invention.

In accordance with the first embodiment of the invention, the device, generally indicated by reference character 10, and illustrated in FIGURES l to 4, inclusive, is formed of planar synthetic resin-ous material of a laminated type well-known in the art. As seen in FIG- URE 6, this material is interconnected using heat-sealing techniques, and is formed by laminating first and second layers of a suitable synthetic resinous material 14 and 16 with a layer of aluminum metallic foil 15, in such manner that the foil is completely protected by the synthetic resinous laminae. Owing to its mechanical strength and resistance to abrasion, Mylar is particularly suitable, and is widely used in the art. Interconnected between portions of the inner surface of the cylindrical wall 11, and extending between the first and second end walls 12 and 13, are a plurality of septums 18, 19, 20, 21 and 22, preferably of a single membranous type such as Mylar of a gauge thinner than that employed in forming the cylindical wall 11 and end walls 12 and 13. The particular `thickness of the septums 18-22 is governed by the requirement that the same have a bursting strength substantially less than the hoop strength of the cylindrical wall 11 and that of the first and second end walls 12 and 13. An opening 23 is interconnected to a short length of tubing 24, to provide means for partial equalization of pressure differentials existing on either side of the septums 18-22, prior lto the rupturing of the same, as will more fully appear. A gas capsule or other convenient source of gas supply 25 is disposed within a chamber 27 formed by the first or upper end wall 12 and the first septum 18, the same being of a type wellknown in the art, which may be controlled through the wall 11 without damage to Ithe same.

Referring to FIGURES 2, 3 and 4, it will be observed that the first, second, third, fourth and fifth chambers 27, 29, 31, 33 and 35, respectively, are erected in serial fashion. Although not essential, it is preferable that the gas contained in the capsule 25 be lighter-than-air at normal atmospheric pressure, so that upon erection of each successive chamber, the same will possess suicient lbuoyancy to pull remaining parts of the device 10 from folded condition with little if any assistance by attending personnel. As each chamber 27-35 inflates, a small amount of gas will travel through the rtube 24 so that, at the point where the interconnecting septum ruptures, the occurrence of the accompanying shock wave will be minimized to a degree where all possibility of damage to the antenna is eliminated. The provision of vent means in the septums avoids also the possibility of the occurrence of sufficient loss of pressure to collapse the antenna.

Upon the complete erection of the device 10, electrical leads 36 may be interconnected by conductive tape 37 or other suitable interconnecting means, or, in the alternative, the device 10 may be manufactured with the leads 36 already connected.

Turning now to the second embodiment of the invention, illustrated in FIGURE 5, the device, generally indicated by reference character 40, differs from the first embodiment principally in the elimination of the septum c-onstruction 18-22, and the substitution of a separate means for progressive inflation. Thus, the device 40 includes a cylindrical wall 42 corresponding to the wall 11, a first or upper end wall 43, a second or lower end wall 44 (shown collapsed), and a supporting platform element 45.

The supporting platform element 45 includes an outer guide ring member 47 to which a plurality of legs 48 are selectively attachable, in which condition the ring member 47 is supported a distance above the ground sufficient to clear the folded portions 49 of the unerected antenna. The ring member 47 includes a generally centrally disposed downwardly :tapering through opening 51, the surface of which is covered with a suitable lubricant to facilitate relative sliding movement between said surface and the outer surface of the cylindrical wall 42.

Disposed within the antenna envelope 41 is an inner guide ring member 53, having upper and lower surfaces 54 and 55, and a generally centrally disposed recess 56 which supports the gas capsule 57. A peripheral tapered surface 58 corresponds in angularity to that of the surface 51, and from a consideration of FIGURE it will be apparent that the configuration of the inner guide ring member 53 is such that it cannot fall through the opening in the outer guide ring member. The surface 56 may also be lubricated to facilitate relative sliding motion with the inner surface of the antenna envelope 41.

Erection is simply accomplished by interconnecting the legs 48 with the outer guide ring member 47, and placing the device in the condition shown in FIGURE 5. The gas capsule 57 is then actuated, wherein the ow of expanding gas will erect the length of the antenna envelope 41 in progressive manner. Where the gas within the capsule 57 is of a lighter-than-air type, the erected portions of the antenna become buoyant, and assist in the pulling up of the unfolded portions 49 remaining disposed beneath the outer guide ring member 47. As the erected portion rises, the antenna envelope 41 will slide between the inner and outer guide ring members 53 and 47.

Turning now to the third embodiment of the invention, as illustrated in FIGURE 9 in the drawings, parts corresponding to those of the -first embodiment have been designa-ted by similar reference lcharacters with the additional prefix 1.

The third embodiment of the invention differs from the first embodiment in the elimination of the gas capsule, and the connection of a tube 60 with the first compart- 4. v ment 127 at an upper end thereof, and at a lower end with a gas generator 62. In this embodiment, the tube remains attached to the first compartment, and goes up with the device as the same is erected.

Turning now to the fourth embodiment of the invention, as shown in FIGURE 10 in the drawings, parts corresponding to those of the first embodiment have been designated by similar reference characters with the additional prefix 2.

The fourth embodiment of the invention differs from the first embodiment thereof in the elimination of the` septums 18, 19, 20, 21 and 22 of the first embodiment, and the substitution thereof of a strip of double-faced adhesive tape which holds together the cylindrical wall 211 to define individual chambers 227-235. If` desired, the tubes 224 may be also incorporated. In :this embodiment, during erection the pressure of the gas breaks the adhesive seal between adjoining chambers as the same are inflated, in much the same manner in which the walls 18-22 are ruptured.

I wish it to be understood that I do not consider the invention limited to the precise details of structure shown and set forth in this specification, for obvious modifications will occur to those skilled inthe art to which the invention pertains.

I claim:

1. In a pneumatically inflatable antenna, an hermetically sealed flexible elongated envelope having upper and lower ends formed of material capable of receiving and conducting an electrical signal, a self-contained capsule having a gas under compression, a plurality of frangible septums interconnected to the inner surface of said envelope to divide the interior thereof into substantially separate chambers, said capsule being initially disposed within one of said chambers adjacent said upper end ofsaid envelope, the septum defining said chamber rupturing upon the development of internal pressure to a predetermined point less than the pressure at which said envelope will rupture to allow said capsule to fall into and inflate successive chambers as said envelope is erected.

2. In a pneumatically inflatable antenna, an hermeti cally sealed flexible elongated envelope having upper and lower ends formed of material capable of receiving and conducting an electrical signal, a self-contained capsule having a gas under compression, a plurality of frangible septums interconnected to the inner surface of said envelope to divide the interior thereof into substantially separate chambers, said capsule being initially disposed within one of said chambers adjacent said upper end of said envelope, :the septum defining said chamber rupturing upon the development of internal pressure to a predetermined point less than the pressure at which said envelope will rupture to allow said capsule to fall into and inflate successive chambers as said envelope is erected, said septum including venting means therein for at least partially equalizing pressure differentials existing between adjacent chambers.

3. In a combination erectable antenna and supporting platform structure, an hermetically sealed flexible elongated envelope formed from material capable of receiving and conducting an electrical signal, said supportingV platform structure including an outer guide ring member, said outer guide ring member having a substantially `centrally disposed opening therein through which said envelope in at least partially inflated condition may pass as the same is erected, an inner member of configuration such as to be supported by said ou-ter ring member substantially in the plane of said outer ring member, and inflating means disposed within said envelope, said inner member being initially sealed within said envelope.

4. In a combination erectable antenna and supporting platform structure, an hermetically sealed flexible elongated envelope formed from material capable of receiving and conducting an electrical signal, said supporting platform structure including an outer guide lring member, said outer guide ring member having a substantially centrally disposed opening therein through which said envelope in at vleast partially inated condition may pass as the same is erected, an inner member of configuration such as to be supported by said outer ring member substantially in the plane of said outer ring member, and inilating means disposed within said envelope, said inner member being initially sealed Within .said envelope, and means supporting said outer guide ring member above a horizontal surface a distance suicient to clear the initially unerected portions of said envelope.

References Cited by the Examiner UNITED STATES PATENTS 511,472 12/1893 Sumorski 52-2 1,285,940 11/ 1918 Chodakowski 343--915 2,718,014 9/ 1955 Mizrach et al 52-2 3,068,477 12/ 1962 Tennyson 343--915 3,095,568 6/ 1963 Aine et al. 343-915 FOREIGN PATENTS 128,502 5/ 1959 U.S.S.R

HERMAN KARL SAALBACH, Primary Examiner. W. K. TAYLOR, E. LIEBERMAN, Assistant Examiners. 

1. IN A PNEUMATICALLY INFLATABLE ANTENNA, AN HERMETICALLY SEALED FLEXIBLE ELONGATED ENVELOPE HAVING UPPER AND LOWER ENDS FORMED OF MATERIAL CAPABLE OF RECEIVING AND CONDUCTING AN ELECTRICAL SIGNAL, A SELF-CONTAINER CAPSULE HAVING A GAS UNDER COMPRESSION, A PLURALITY OF FRANGIBLE SEPTUMS INTERCONNECTED TO THE INNER SURFACE OF SAID ENVELOPE TO DIVIDE THE INTERIOR THEREOF INTO SUBSTANTIALLY SEPARATE CHAMBERS, SAID CAPSULE BEING INITIALLY DISPOSED WITH- 